Cooled rotary pump



April 27, 1965 R. A. BIELEF ELD 3,180,569

COOLED ROTARY PUMP Filed May 21, 1962 5 Sheets-Sheet 1 [F1 1 IV 12 /0/45 J0 30 an M [L "2& 1 mi Q ,zW

April 27, 1965 R. A. BIELEFELD COOLED ROTARY PUMP April 27, 1965 R. A.BIELEFELD COOLBD ROTARY PUMP 5 Sheets-Sheet 3 Filed May 21, 1962INVENTOR. A 01; 4. fl/AZEFEM BY Q0 ;W

April 27, 1965 R. A. BIELEFELD 3,180,569

COOLED ROTARY PUMP Filed May 21, 1962 5 Sheets-Sheet 4 INVENTOR. A0ZF A.BAH/EH9 April 27, 1965 R. A. BIELEFELD COOLED ROTARY PUMP 5 Sheets-Sheet5 Filed May 21, 1962 INVENTOR. P00 '4. 5751:7220

QVAV

ATTOAA/EYS controlled peripheral pressure.

United States Patent'O 3,180,569 CQOLED ROTARY PUMP Rolf A. Bielefeld,Saint Joseph, Mich, assignor to Gast Manufacturing Corporation, BentonHarbor, Mich, a

corporation of Michigan Filed May 21, 1962, er. No. 196,267 11 Claims.(Cl. 230-209) This invention relates to rotary pumps, and moreparticularly to air-cooled, rotary vane pumps for gaseous media havingcontrolled gas inlet and exhaust features.

The efliciency and dependability of a rotary pump, especially a rotaryvane pump, depend to a large extent upon low operating temperatures ofthe pump. it is well known to those in the field that rotor hubtemperatures often reach undesirably high values because of theinability of the hub to effectively dissipate its heat to the outside.Only a limited amount of the heat in the hub is conducted out throughthe end shafts. Moreover, this heat conducted through the end shaftstends to overheat the bearings supporting the end shafts in the pumphousing end plates.

The bearings mounted in the end plates are further subjected toadditional heat caused by frictional contact of the high speed rotatingpumping vanes against the inner walls of the end plates. The adverseeffect of these factors is further magnified by the present lack of asatisfactory housing structure to achieve proper cooling of the exteriorof the entire pump in an economical manner.

7 Another shortcoming of present rotary pumps is the lack of asimplified positive control system of the pump inlet and exhaust gasesto enable proper filtering without substantially detracting from thepumping eflicie'ncy, or to enable rapid operational changeover of theunit from a filtered compressor to a mufiled vacuum pump.

Another feature of conventional rotary vane pumps which detracts fromefiiciency and output is the high pressure gaseous blow-byor slippagewhich passes beneath the lower edges of the vanes between the end platesand the ends of the rotor hub. This slippage creates operational lossesand raises internal operation temperatures considerably.

To obtain optimum elliciency, rotary vane pumps must not only make aneffective seal against the end walls, but also must seal effectivelyagainst the peripheral housing wall. The pressure of the individualvanes against the housing Wall must at all times be great enough to keepthe vanes in contact with the peripheral wall. Yet, the pressure of thevane against the peripheral housing wall must not be so great as tocause undue wear of the vanes. Various methods of pneumaticallybalancing or cushioning the vanes are presently utilized in efforts toaccomplish this However, these conventional methods generally lack areally accurate or controlled vane cushion since the gaseous pressuresunder the vane tend to vary largely. I

It is an object of this invention to provide a rotary pumpwithgreatlyimproved efiiciency and reliability over an extended periodof operating time due to a uniquely cooled structure. The interior ofthe pump which includes the rotor hub and the end shafts is efifectivelycooled. Further, the hearings in the end plates around the end shaftsare maintained in'a cool state by special end plate cooling. Moreover,the exterior housing of the pump is efiiciently and economically cooledby a unique flow pattern of cooling air. In addition, the internalcooling, end plate cooling and exterior housing cooling are all eifectedhlddhdh Patented 2?, i955 by simultaneously blower means operateddirectly on the end shafts of the pump. The end plates not only maintainthe bearings in a cooled condition, but also have a heat flowrestricting darn structure substantially reducing the conduction offrictional heat from the inner walls of the end plates to the portionsof the end plates mounting the bearings.

It is another object of this invention to provide a pump 7 having a basecons ruction which constitutes a manifold for directing pump inlet andoutlet gases, for filtering or mufiling gases, and for directing coolingair. The manifold is reversible with respect to the pumping unit toenable a special filter-receiving chamber (when the unit serves as acompressor) toalternately constitute a mufflerreceiving chamber for usewith the unit when operating as a vacuum pump. The manifold receives anddirects air propelled by the blower on the end shaft.

it is another object of this invention to provide a vane type pumphaving an accurately controlled air cushion under the base of each vaneto provide optimum constant contact of the outer vane edge against theinner housing peripheral wall. The controlled air cushion enablesaccurate cushion pressures under the vane even though the cushioned gaschanges in temperature during the cycle.

These and other objects of this invention will be apparout upon studyingthe following specification in conjunction with the drawings in which:

FIG. 1 is a side elevational view of the novel pumping apparatus;

PEG. 2 is an end view of the apparatus as viewed from plane Hll of FIG.1;

PEG. 3 is a side elevational sectional view taken on plane IlI--Ill ofFIG. 2;

FIG 4 is a sectional view of the apparatus taken partly on plane IV-IVand partly on plane IV'-IV' ofFIG. 1

showing the apparatus adapted to operate as a compressor;

PEG. 5 is a fragmentary sectional View showing the pump rotor and vanesin the housing shell and showing the novel vane cushioning means;

FIG. 6 is a top plan view of the manifold portion of the base of theapparatus;

FIG. 7 is a side elevational slightly enlarged view of the completebase;

FIG. 8 is an end elevational viewof one of the end plates adjacent thefan of the apparatus illustrated in FIG. 3;

FIG. 9 is an end elevational view of the end plate adjacent the drivepulley illustrated in FIG. 3;

FIG. it) is a fragmentary partially sectioned view of a slightlymodified double blower arrangement which can be used instead ofthesingle blower illustrated in FIG. 3; and

P16. 11 is a fragmentary sectional view of the apparatus with the pumpreversed on the base to enable operation as a vacuum pump.

Basically, the invention comprises a rotary pump including a hub andattached end shafts having an elongated cooling fluid passagewaytherethrough. Cooling air is drawn through the passageway by a. bloweror fan means mounted on the. end shaft means. The blower means may be ofthe centrifugal type. It can be mounted over radial outlet openings inone end shaft, or may be mounted to suck air out an annular passagewayin an end shaft.

The pump has an outer shroud over the'pump housing, including an end airinlet or one end adjacent a fan, and" enclosed transverse fins on thehousing to direct the cooling air flow. The fins are spaced from theshroud on the cooler, low pressure zone of the pump to allow airentering into the end shroud opening to flow into the intermediatetransverse spaces between the fins. The fins are inclose proximity tothe shroud adjacent the hotter, high pressure zone of the pump housingto uniformly cool it by forming substantially closed conditions betweenthe fins.

The housing end plates include circumferential, coolingfluid passagewaysaround the outer periphery of the bean ings mounted in the end plates.The circumferential passageways receive cooling air from the fan on theend shaft. The inlet to the circumferential passageway is divided by abaffle to form separate cooling air pathscausing high-velocity,low-resistance cooling-air flow over the hotter, high pressure zone ofthe pump, and causing separate higher-resistance, cooling-air fiow overthe cooler low pressure zone of the pump.

Each circumferential passageway in the end plates includes an annular,radially-inwardly-directed recess or cav-. ity portion between the innerwall of the end plate and the portion of the end plate .in which thebearing is mounted. This provides a heat-flow restricting damsubstantially lessening the conduction of heat from the inner wall ofthe end plate to the bearing.

A unique combination supporting base and manifold is removably attachedto the bottom of the pump and in cludes ports and passagewaysto directcooling air to the end plates, to direct and filter inlet air or gas tothe pump,

and to direct compressed outlet air or gas. The manifold is readilyreversible to enable rapid conversion of the pump from a compressor'to avacuum pump, with the filter-receiving chamber then comprising amufiler-receivpreferably include a cool-air inlet port allowing entry ofair under the extended vanes due to their position adja-'' cent the airinlet portion of the pump, a bleed port located part-way around the pumpand communicating with the slots under partly depressed vanes, and anexhaust port spaced operationally beyond the air outlet for the pump 'tocommunicate with the slots under completely depressed vanes to exhaustthe heated, compressed cushioning air. These allow the influx of coolcushioning air during each cycle, and accurate control of the aircushions.

External cooling Referring now to the drawings, pumping apparatus 14) asexternally viewed includes a'combination manifold and base 24, enclosingshroud 12, and a drive pulley 18 mounted .on an end shaft 16. The termentire base is intended to normally include the manifold portion.

The shroud 12 may comprise pre-formed thin material 7 such as sheetmetal. shells secured together by bands 20 (FIG. 1) around pairs offacing semi-circular projections forming posts 22 (see FIGS. 1 and 4);It may be formed of one continuous piece instead of two, and may includea portion serving as a guard over pulley 18. It fits down around themani fold part of the base as in FIG. 4 to enclose the' apparatus. Theshroud hasa plurality of openings forair inlet and outlets as explainedhereinafter.

The base includes a chamber for receiving a filter 26- when the unit isused as a compressor (FIG. 4) or a muliier 326 connected together. whenthe unit is used as a vacuum pump (FIG. 11). The base may be formed oftwo parts by suitable means such as studs 202 (FIG. 2) ort-the -eoinpiete base maybe of an integral construcnjjsh Enclosed within shroud l2and mounted upon the base as by studs 2th) is the main pump housing 23(FIG. 3).

It is shown formed of two half (The unit will first bedescribed as acompressor.) It has a plurality of transverse fins .30 on its outerperiphery. On the low pressure air intake side of the pump (the leftside in FIG. 2 and the right side in FIG. 4), fins 30 are substantiallyspaced from shroud 12 to provide an air flow space 32 through whichcooling air entering the axial end opening 33 (FIG. 3) in the shroud,may fiow after passing through the outer portion 106 of centrifugal fan40. Air drawn through'opening 38 passes through fan 40, through space42, then space 32. Here a change of direction from longitudinal totransverse occurs. The air then flows between the fins in spaces 48'(FIG. v3). Pins 30 are in close proximity to shroud 3.12 on theopposite side of the pump where the air pressures inside the pump aregreater. (as explained hereinafter) andthus the temperature is higher.The spaces between adjacent fins '30, the pump housing external surfaceand the inner surface of the shroud combine to form substantially closedconduits for uniformly distributingthe cooling air over the hot portionof the pump. After theair passes between the fins 30 under the bottomandaround the top of the pump (FIG. 3), it flows out .outlet port 50 inthe side' of the shroud (FIGS. 1 and 4).

Internal cooling Referring to FIG. 3, pump housing 28 includes 'agenerally cylindrical central housing'portion 7d, a first end plate 72on the drive end, and a second end plate 74 on the fan end of the pump.Within the housing is rotatably mounted a rotor means including centralrotor hub '76, integral end shafts 78 and 80, and 'slidably mountedvanes 82 (FIGS. 3 and 4). The vanes 82 fit in generallyradially orientedslots extending the lengthof the hub, such that the ends of the vanescontact the inner-walls 84 and 86 of the end plates '72 and 74. Thevanes also contact the inner peripheral wall 88 of the cylindricalportion of the housing during operation of thepump.

The end shafts arerotatably mounted in the end plates by suitablebearings, 90 and 92with adjacent seals 94 and 96. The end platesinclude'caps and 112.

'In the form of'the invention illustrated in FIG. 3, on end shaft 86 isattached a centrifugal fan 40 which includes an outer section 100 and aninner section 102, divided by a partition 194. The fan has a centrifugalaction. Fan 40 is secured to end shaft 80b a collar 114 and set screw116, orother equivalent-means- In order to provide proper cooling of theinternal structure of the pump, the end shafts 78 and ,Sdand the'hubl76are provided with a centralpassagewaylZtl 'andradial outlet ports 12 2in end shaft 30.. These ports communicate with inner section 162 of fan4tl'to enable air to be drawn through passageway 126, exit at ports 122,and then into passageway 42 between the housing and the shroud to mixwith air introduced at port 38 of the shroud. .This interior passagewaythus cools both end shafts adjacent bearings 9 and 92 and also conductsheat away from the central rotor hub for optimum efliciency. It will benoted that the cooling occurs simultaneously with operation of the pumpsince the fan is mounted directly upon the end shaft, and that the samefan cools both the'interior and the exterior.

Instead of the singlefanshoWninFIG. 3 and described above, it issometimes. desirable to utilize fan 4% of a conventional construction(see FIG. 10) on end shaft 80 to direct air around the outside of the.unit, and to utilize a separatecentrifugal fan 3% formed integrallyWith.

shiver 18 to suck. air through passageway inthe opposite direction. Inthis instance an axial inlet 3W2 in end shaft 80 will suffice insteadof'radial openings 122;

. partition 164 on the manifold base.

Cooled end plates The end plates 72 and 74 include circumferentialpassageways 131i and 132 respectively, encircling bearings 91 and 52. Aportion of the cooling air entering at 33 flows through thesecircumferential passageways to cool the end plates. These passagewaysare enclosed by end caps 110 and 112 attached to the end plates as bybolts 111. More specifically, air entering at 38 (FIG. 3) passesdownwardly into space 149 and is propelled by the outer section 169 ofthe fan into passageway 142 over the deflecting diagonal partition 141(FIG. 3) on the manifold base. It then flows into passageway 132 and outthe lateral exhaust port 14-8 (FIG. 2). It will be noted from FIG. 2that a baffle 150 divides the inlet to this circumferential passageway132 into two portions. Part of the air flows (to the right) through ashort, low flow-resistance, radial segment comprising about 90 of thecircumferential passageway and out through the outlet port 148. Anotherportion passes (to the left) around the longer, higher-resistancesegment comprising about 270 of the passageway and out the outlet port148. The low resistance segment is adjacent the high compression Zone ofthe pump which is the hottest. This Zone demands more coolling than thelower compression zones which are cooled by the second flow path.Openings close to the heat dam are provided in the radial supportflanges or baflies 152 and 154 to allow the cooling air to flow throughthem in the long segment. I

Not only is end plate 74 cooled in this fashion but also end plate 72,The cooling air entering at port 32 (FIG. 3) and flowing into space 140passes partially through open space 169 between the supporting bracketor stand 14 and lower base portion 24. It flows clear under the pump andthrough space 162 over the diagonal deflecting It then flows intocircumferential passageway 1311 where the flow is divided into twopaths, one being a short, low flow resistance path over the highcompression hot zone of the pump, and the other being a higherresistance longer path over the cooler low compression portions of thepump just as in the opposite end plate. The air then emerges at exhaustport 176 (FIG. 1). The walls ofthe exhaust port 170 may be integral witheither the end plate or shroud.

To further protect bearings 90 and 92 from heat created by frictionalcontact of the ends of the sliding vanes 32 with the inner walls 84 and86 of the end plates 72 and 74, a heat-flow restricting dammingstructure is provided in the end plates as shown in FIG. 3. Thiscomprises annular, radially-inwardly directed cavities or recesses 176and 178 in end plates 72 and 74, respectively extending a substantialdistance between the bearing-receiving recess in the end plates and theinner wall of the end plate. Cooling air circulating through thecircumferential passageways 130 and 132 thus effectively conduct theheat away from the inner end plate walls. This constitutes in effect aheat-flow damming structure since only a small metal partition 23 existsthrough which heat can be conducted.

Combination manifold base The base not only comprises a removablemounting means for the pump, but it also constitutes a manifold fordirecting air flow and for receiving a filter or mufiler. The detailedstructure of the manifold base can be seen more clearly in FIGS. 6 and7. It comprises essentially a generally rectangular, lower portion 14and an upper portion 24- thereabove and having an open bottom. It inberto the pump inlets 2443 and 242 (FIGS. 8 and 9) in the end plates whenthe unit is adapted to operate as a compressor as shown in FIG. 4. Thisallows air or gas passing through the filter to pass into the pump to becompressed. The other two openings 214 and 216 in the base constituteoutlet ports adapted to communicate with the pump outletpassageways 246and 243 in the end plates. This allows compressed air to pass from thepump into a small end chamber 222 in the base (FIG. 6) and then outthrough compressed gas-exhaust port 220 to which a suitable conduit (notshown) may be attached. To separate compressed gas in chamber 222 fromthe uncompressed inlet gas in the filter chamber 2% under partition 203,an elongated vertical partition 224 is provided to extend across thewidth of the base. i

The portion 230 of partition 20? adjacent outlet port 220 and thatportion 232 on the opposite side are raised at the edge, and they tiltdownwardly on an angle toward the center (see FIGS. 2 and 7). providesmooth deflecting surfaces for the cooling air passing beneath thehousing between fins 3119 as explained heretofore.

Ports 211i and 212 in the base and ports 214 and 216 cooperaterespectively with the inlet and outlet passageways in the end plates ofthe pump housing, in the following manner. Referring to FIGS. 8 and 9end plates 72 and 74 are shown without their end caps 11th and 112 sothat radial bracing flanges 150, 152 and 154 are shown clearly. The endplates 72 and 74 have inlet passageways 24d and 242 respectively, andoutlet passageways 246 and 248 respectively.

When air is to be compressed, it is supplied to the pump by being drawnthrough port 38 by fan 40 and downwardly through space and space 161)(FIG. 3) and then up through filter 26. It then kows through openings219 and 212 in the base 24, up through inlet ducts 24d and 242 in theend plates and between the vanes 82 inside peripheral wall 83. It isthen compressed by the rotor means and discharged through ducts 244 and246 in the end plates, down through openings 214 and 216 in the intochamber 222, and out through discharge port 220.

When a vacuum pump operation is desired (see FIG. 11) the novel manifoldstructure enables the unit to be quickly changed from the filteredcompressor to-a muffled vacuum pump unit. This may be elfected by simplyremoving bolts 2% out of the threaded base openings 251, rotating thepump with respect to the manifold base, and replacing bolts 2%. Thefilter chamber 2% thereby becomes a mufiler-receiving chamber by slidingout filter 26 and inserting mufiler 326.

In the operation of the unit as a vacuum pump, it will noted that therotor 76 and vanes are reversed with respect to the base so that port2213 becomes an inlet port. The chamber or line to be evacuated is thusattached over port 220. The evacuated gas then passes into port 220, uppassageways 249 and 242, around rotor 76 in a clockwise direction asviewed in FIG. 11, down passageways 246 and 248 and into the chamberabove the mufller 326. This muffler may contain conventional resonancebaffles 321) or absorption structure 322 such as steel wool. The mufflerincludes a lower partition 324 preventing the hot evacuated gases frompassing into chamber 161? where cooling air is flowing to end plate 72(FIG. 3). Thus the evacuated hot gases pass out the sides of the muflleras indicated by the arrows in PEG. ll.

Controlled vane cushion In FIG. 5, thefragmentary sectional view showsthe pump housing (without its cooling fins) with the inner peripheralwall 88 defining the cylindrical chamber in which rotor 30%? iseccentrically mounted. The rotor axis is parallel to the axis of thecylindrical chamber 83. Formed in the rotor over the length thereof is aplurality of generally radially positioned vane-receiving slots 362.Each of these slots preferably has an enlarged cavity 324 at the basethereof as claimed in my co-pending application Serial No. 181,618,filed March 22, 1962, now atent No. 3,138,321. This cavity 3194 may, inthis inven- Surfaces 23d and 232 to a completely depressed position asshown by vane "82. When the depressed vane begins to extend again, itpasses the air inlet port 244 inciudingrrecess 241 in the end plate. Thevane continues to draw in airuntil it reaches the position of vane 82.As these vanes pass around with the rotor hub, they are slowly depressedinto their slots as the air is compressed between therotor'hub and theWall 88. When the exhaust port 246 is reached, compressed air isexpelledwhile the vane continues to'be depressedinto the slots to itsmaximum depressed position as at vane 82', and the cycle then beginsagain. I

Duringoperation, the movement of each vane in its respective slot causessequential compression and evacuation of the air or gas trappedunder thevane. The pressure under'the vane tends to exaggerate vane tip pressureagainst the housing wall. Vacuum tends to keep the vane from continuouscontact with the wall. methods have been denied in attempts todynamically balance the vane including arcuate channels in the endplates or rotor ends, and including radial passageways in or adjacentthe vane. At best, these allow constant pressure equalization, but donot provide accurate vane tip pressure control over the criticalportions of the vane movement cycle. More specifically,'it has beenfound that the vanes tend to move out of contact with the peripheralhousing wall at and adjacent (just beyond) the exhaust port'of the pump.Consequently, it hasbeen found to be greatly advantageous to achievelarger vane 32d of the vane cavities are not exposed to a vent as thevane tip approaches and passes exhaust port 246 (this exhaust port maybe either in the end plates, the peripheral housing wall, or both).Since the vane is compressing gases in the slot base 324), a pressurecushion is created forcing the vane tip into a greater pressure contactwith the wall 88. This continues as the vane passes the exhaust portuntil it is adjacent the inlet port i.e. where it begins to extend outof its slot. At that time, slot base 329 (preferably wall 304)communicates with channel 322 and outlet port 321 to exhaust the hotcompressed cushion air into the end plate passageway (or if desired tothe atmosphere). If the unit is operating as a vacuum pump, on the otherhand, port 321 allows entry of atmospheric air into the slot base whichwill have beenlargely evacuated'by escape of the cushion alongside thevanes.

Thus the new air provides pressure for continuous vane tip contact.

As the-vane continues to move with the rotor with the unit operating asa compressor, slot base 326 next communicates with arcuate channel orpassageway 324- which way around as the vane is in the initialdepression stages with the slot base chamber being smaller. The exactlocation of the last portion of this channel 326 enables an exactadjustment of the volume of gases in the vane cushion. This is caused bya limited bleeding or venting. The small amount ofair exchange enablesan exact adjustment Various of the cushion to provide the optimumcushioning in the highcornpression zone of the pump. As -stated, theexact location of one-or more'bleed ports determines thefinal cushionpressure. These threeports thus cooperateto first take in cool air,accurately bleed off a small percentage of the warm, partiallycompressed airto'set the'air cushion at the exact desired amount, and.then exhausting the compressed hot cushion air to enable it toagainreceive cool cushion air. In the pump illustrated, each of theports 3231, 323 and-325 cooperating respectively withthe passageways322, 324 and 325 is preferably formed in the end plate as in end plate'74 in FIG. 3. They communicate through theannular recess 178 to thecircumferential passageway 132. The other end platc 72 can be providedwith similar parts. As shown more specifically in PEG. 2, the cool airinlet 323 is adjacentthe start of the 270 passageway, the bleed port 325is part way around the 270 passageway, and the exha'ustport 321 isassociated with the flow path in the circumferential passageway. Ifdesired, a pump may utilize thisporting feature without end platepassagewaysby porting to theatmosphere.

Conceivably channels 324 and 326 can be joined into one continuouspassageway to both provide cool inletcushion air and bleed it to theproper volume before the'vane causes cushion compression. However, ithas been found desirable to provide a non-ported'area. 331 between thepassageways 324 and 326, and located such. as to eliminate slot baseventing just before the vane passesthrough its most extended position. 7The vane, as it extends the final amount, thereby causes a small vacuumto occur in the slot base, tending to reduce vane-tip contact pressureat this point and thereby reducing wear considerably; Thus, by using oneor more ports at specific locations to'vent the vane cushions only atcrucial moments when they are under specific different pressurepotentials, excellent control of venetip pressure is achieved. Theresults achieved with the-unit operating as a compressor are (l) apressure cushion when the vane. passes is most depressed in the slot tokeep it in firm contact with thewall thereby preventing slippage, (2).accurate bleeding and control of this pressure cushion, (3) completeaspiration of cushion cool air witheach cycle, and (4) a vacuum cushionwhen the vane is in its most extended position to minimize wear.

the pump and the exterior of the bearings, and supplies air to becompressed bypassing it through filter 26 and up through the manifoldopenings. The manifold directs the compressor inlet and outlet air orgas through filter 26 and openings 210, 212, ZM-fand 216, it directs theend plate air. flow. over surfaces 141'and 164, and it creates a smoothflow under the pump exterior with surfaces 2 3% and 232'. Reversal ofthe manifold allows operation of the compressor as a vacuumpump duringwhich the manifold base directs the evacuated gas through port 22%),into the pump chamber, and through themuflier 32-. The unit is capableofremarkableefiiciency due to its cool operation, and also due to thecontrolled vane-contact pressure. It is relatively compact in spite ofits elaborate cooling system and manifolding characteristics.

Certain obvious modifications of this-apparatus within the inventiveprinciples taught may bemade'without departing from the scope of theinventiom Such modifications are deemed part of this invention, which'isto be limited only by the appended claims and the reasonable ity oftransverse cooling fins and intermedai't'e spaces on the housingexterior; a shroud generally around said housing and including coolingair inlet and outlet means, and said shroud and fins being relativelyspaced from each other adjacent said low compression zone to allow airto pass from said shroud inlet to the spaces between said fins;-saidshroud and fins being closely positioned with respect to each otheradjacent said high compression zone to cause said spaces to formsubstantially closed passageways whereby air can be uniformly directedover the heated high compression area for effective cooling; and coolingfan means adapted to propel air over said fins within said shroud.

2. A rotary compressing pump comprising: a housing including end walls;a rotatable rotor hub within said hous ing including slidable vanes andhaving end shafts; said rotor being eccentrically mounted Within saidhousing to create a low compression pumping area and a high compressionpumping area; a plurality of transverse fins and intermediate spaces onthe housing exterior; a shroud generally around said housing andincluding cooling air inlet means on one end, and outlet means adjacentsaid high compression area; said transverse fins being displaced towardthe side of said housing having said high compression area into closerelationship with said shroud to define a plurality of substantiallyclosed cooling passageways between said fins, shroud, and housing touniformly conduct cooling air over said high compression area; and acooling fan adapted to propel air over said fins Within said shroud.

3. A rotary compressing pump comprising: a housing including end walls;a rotatable rotor hub within said housing including slidable vanes andhaving end shafts; said rotor being eccentrically mounted within saidhousing to create a low compression pumping zone and a high compressionpumping zone; a plurality of transverse films and intermediate spaces onthe housing exterior; cooling fan means mounted on at least one of saidend shafts; a shroud around said housing; an air inlet in said shroudadjacent said fan; a passageway through said end shafts and said hubincluding outlet means in one end shaft adjacent said fan means; saidshroud and transverse fins being relatively spaced from each otheradjacent said low compression zone to allow air down through saidpassageway and through said air inlet to pass into said spaces betweensaid fins; said shroud and fins being closely positioned with respect toeach other adjacent said high compression area to cause said spaces toform substantially closed conduits; and outlet means in said shroudadjacent said conduits.

4. A rotary pump comprising: a pump housing; rotatable pumping means insaid housing including rotor means and end shafts on said rotor means;cooling fan means mounted on at least one of said end shafts and adaptedto rotate with said shaft; shroud means spaced from and around saidhousing including air inlet and outlet means; cooling fins on saidhousing to direct air flow around and conduct heat from said housing; anair flow passageway through said end shafts and said rotor meansincluding outlet means adjacent said fan means; said housing includingend plates; each of said end plates having a circumferential coolingfluid passageway including an inlet and outlet within the enclosure ofsaid shroud; and said fan means being operably associated with saidfins, said air flow passageway, and said circumferential passageway tosimultaneously cool the pump housing exterior, the pump interionand theend plates, while the pump is in operation.

5. A rotary pump comprising: a housing means including an innerperipheral wall and a pair of end plates; rotor means mounted in saidhousing and including end shafts supported by and extending into saidend plates; bearing means mounted in said end plates for said endshafts; circumferential cooling fluid passageways around said bearingmeans in said end plates; air directing shroud lb means around saidpump; and blower means mounted on at least one of said end shafts andadapted to propel cooling air directed by said shrouds into saidcircumferential passageways to maintain cool bearings.

- 6. A rotary pump comprising a housing including two end plates;eccentrically mounted rotor means in said housing including end shaftsrotatably mounted in said end plates; said pump including a pump fluidinlet adjacent the relatively large low compression zone of the pump andincluding a compressed fiuid outlet adjacent the relatively small highcompression zone of the pump; a cooling fluid passageway in each of saidend plates substantially encircling said end shaft; a cooling fluidinlet means to each of said passageways between said high and lowcompression zones; andeach of said cooling fluid inlet means beingdivided to create a high velocity,

low-fiow--resistance coolant flow path past said relatively small, highcompression zone, and to create a separate, lower velocity,higher-fiow-resistance coolant flow path past said relatively large, lowcompression zone.

7. A rotary pump comprising: a housing means including an innerperipheral wall and a pair of end plates; rotor means mounted in saidhousing and including end shafts supported by and extending into saidend plates; bearing means mounted in said end plates for said endshafts; circumferential cooling fluid passageways around said bearingmeans in said end plates; each of said end plates having an inner wallin rubbing contact with portions of said rotor means; and each of saidpassageways including a circumferential, inwardly radially directedcavity extending between said bearing means and said inner wall therebyforming a heat-flow restricting darn.

8. A combination manifold base for a rotary compressor pump having inletand outlet ports adjacent the bottom thereof, comprising: a base housingincluding means for connecting and aligning said base to a pump; an airinlet in said base; a filter-receiving chamber in said base adjacentsaidair inlet; first air porting means in the upper portion of said baseadapted to communicate with the inlet port of a rotary pump arid withsaid filterreceiving chamber; second air porting means in said baseadjacent the upper portion thereof and adapted tocornmunicate with theoutlet port of a rotary pump; and passagewa means and an exhaust outletin said base communicating with said second air porting means to controlthe pumped air.

9. The base in claim 8 wherein said first and second air porting meansare generally symmetrically arranged, wherein said base is removablyattachable to the pump, and wherein said filter retaining chamber isadapted to retain a muliler such that said base may be rotated to enablesaid pump to operate as a vacuum pump.

10. A rotary pump comprising a housing including two end plates; pumpingrotor means mounted in housing between said end plates and having a pairof end shafts in bearing contact with said end plates; inlet and exhaustports in said housing adjacent the bottom thereof; a generally flatmanifold under said pump and removably secured thereto; said manifoldhaving a lower air inlet and a filtering chamber communicatingtherewith; a pumping fluid outlet in the top of said manifoldcommunicating with said filtering chamber and said inlet port in saidpump housing; an exhaust entry port in the top of said manifoldcommunicating with said pump exhaust port in said hous-. mg; an exhaustchamber in said manifold communicating with said exhaust entry port andhaving a pressure port leading outside said manifold; cooling airdirecting surfaces on said manifold associated with said end plates ofsaid housing to direct cooling air thereto; and blower means capable ofpropelling air to said cooling air directing surfaces and said manifoldlower inlet.

11. A rotary pump comprising a housing including two end plates; pumpingrotor means mounted in said housing between said end plates and having apair of end shafts in bearing contact with said end plates; inlet andexhaust l3; ports in said housing adjacent the bottom thereof; agenerally flat manifold under said pump and removably secured thereto;said manifold having a lower air inlet and a filtering chambercommunicating therewith; a pumping fiuid outlet in the top of saidmanifold communicating with said filtering chamber and said inlet portin said pump housing; an exhaust entry port in the top of'said manifoldcommunicating with said pump exhaust port in said housing; an exhaustchamber in said manifold communicating with said exhaust entry port andhaving a pressure port leading outside said manifold; cooling airdirecting surfaces on said manifold associated with said end plates ofsaid housing to direct cooling air thereto; a shroud around said housingand having an air entry port; and a blower means mounted on at least oneof said end shafts adjacent said shroud, air entry port, whereby saidblower means propels air to enable said shroud and air directingsurfaces to direct cooling air to said end plates and propels air tosaid manifold lower inlet.

Pfeiffer 2302l0 Berges 2302l1 Houghton 230210 Ahlen et a1 230-2l1 XLindhagen et al 230-2 ll X Petersen 2 30152 Hockel et al; 230-210Briscoe 230152 Blackman 230-211 X FOREIGN PATENTS LAURENCE'V. EFNER,Primary Examiner. ROBERT M. WALKER, Examiner.

1. A ROTARY COMPRESSING PUMP COMPRESSING: A HOUSING INCLUDING END WALLS;A ROTATABLE ROTOR MEANS WITHIN SAID HOUSING; SAID PUMP HAVING A LOWCOMPRESSION PUMPING ZONE AND A HIGH COMPRESSION PUMPING ZONE; APLURALITY OF TRANSVERSE COOLING FINS AND INTERMEDIATE SPACES ON THEHOUSING EXTERIOR; A SHROUD GENERALLY AROUND SAID HOUSING AND INCLUDINGCOOLING AIR INLET AND OUTLET MEANS, AND SAID SHROUD AND FINS BEINGRELATIVELY SPACED FROM EACH OTHER ADJACENT SAID LOW COMPRESSION ZONE TOALLOW AIR TO PASS FROM SAID SHROUD INLET TO THE SPACES BETWEEN SAIDFINS; SAID SHROUD AND FINS BEING CLOSELY POSITIONED WITH RESPECT TO EACHOTHER ADJACENT SAID HIGH COMPRESSION ZONE TO CAUSE SAID SPACES TO FORMSUBSTANTIALLY CLOSED PASSAGEWAYS WHEREBY AIR CAN BE UNIFORMLY DIRECTEDOVER THE HEATED HIGH COMPRESSION AREA FOR EFFECTIVE COOLING; AND COOLINGFAN MEANS ADAPTED TO PROPEL AIR OVER SAID FINS WITHIN SAID SHROUD.